Containment sump

ABSTRACT

A containment sump which is to airtight sealingly mounted in conjunction with a collar that is mounted on a fuel tank. The containment sump, the collar and the fuel tank are all constructed to have a double walled thickness. The containment sump includes a protrusion assembly which forms a series of grooves. A vacuum is to be drawn with the coupled air gaps between the tank, the collar, containment sump and a top hat that is mounted on the containment sump with this vacuum to be conductible through all areas of the air gap which is permitted by the grooves located between the protrusions. The protrusions keep the air gap open by preventing flush abutting contact between the walls of the containment sump. A vacuum gauge is mounted in conjunction with the containment sump to read the amount of vacuum that will have been drawn within the air gap-arrangement. The vacuum gauge is located within the internal chamber which is formed interiorly of the collar, the sump and the top hat.

This Application is a Divisional of Ser. No. 10/997,659 Filed on Nov. 23, 2004 with Applicant Electing claims 1-7

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the construction of underground fuel tanks and more specifically to a way to determine if there is any leakage occurring in conjunction with the underground fuel tank.

2. Description of the Related Art

It is common to mount fuel tanks underground. Such fuel tanks are located underground in gasoline and diesel fuel filling stations for automobiles and trucks. Underground fuel tanks are also utilized in conjunction with heating oil.

There are specific specifications required by state, federal and local municipalities concerning the installing of fuel tanks underground. These specifications require that the fuel tank must be constructed to be of a double wall thickness. Between the walls of the tank there is to be located an air gap. Within that air gap there is to be drawn a vacuum. A vacuum gauge is connected to the air gap. If at any time by reading of the gauge it is ascertained that the vacuum is being lost, this will indicate to the reader that there is a leakage within the tank. Any leakage within the tank will immediately require that the owner of the tank remove the contents of the fuel from the tank and replace the tank thereby preventing any leakage of the fuel from the tank to the ground.

The specifications on installing of tanks also require the tank to be mounted generally four to five feet underground. Fuel tanks are manufactured with a collar with this collar being mounted on what is referred to as the top end of the fuel tank. This collar is normally installed at the tank manufacturer but can be installed at the installing location. The collar includes a double wall and is generally no more than three to four feet in diameter. The air gap of the collar couples directly with the air gap of the tank. The manufacturer of the tank then installs a vacuum gauge in conjunction with the air gap of the collar. If a vacuum is capable of being drawn and held within the air gap, then the manufacturer of the tank knows that the tank is completely sealed and will not leak when fuel is supplied to within the tank. The manufacturer of the tank can now ship the tank to the installing location.

At the installing location, the installer cuts through the upper portion of the collar exposing the air gap. A containment sump, which is basically in the shape of a tube about the same diameter of the collar, is to be placed on top of the collar. This containment sump is open ended so that the internal chamber of the containment sump connects with the internal chamber of the collar. The containment sump will generally be made of fiberglass, as is also the collar, as also the tank. There is an air gap located between the double walls of the containment sump which connects with the air gap of the collar. The upper end of the containment sump is then closed by a top hat which also includes a double wall which has an air gap which connects with the air gap of the containment sump. One of the primary purposes of the containment sump is to locate the top hat at ground level. Other purposes are for the containment of any leak or spills during filling of the fuel tank. The sump also has the ability to detect any leak in the fuel tank. Access to the containment sump has to be provided at ground level. Within the containment there will be located a fuel filling pipe that is utilized during filling of the fuel tank. Also enclosed within the containment sump is a vacuum gauge which indicates the vacuum is being maintained within the air gap located between the containment sump, the top hat on the containment sump, the collar and the fuel tank.

There is a need to insure that when a vacuum is drawn within this air gap arrangement that the wall of the containment sump doesn't collapse on itself which would prevent the even distribution of the vacuum between the top hat, the containment sump, the collar and the fuel tank.

SUMMARY OF THE INVENTION

A first basic embodiment of the present invention comprises a double walled containment sump adapted for use with a double walled fuel tank. The containment sump is defined as comprising a fiberglass housing having a first internal chamber with this housing being tubular having a first open end and a second open end. The housing has a first walled structure with this first walled structure being constructed of a first inner wall located in juxtaposition with a first outer wall forming a first air gap therebetween. The first open end is adapted to be airtight sealingly connected to a tank collar on which is mounted a fuel tank. This air gap includes a protrusion assembly which functions to maintain spacing of the double wall of the sump. A top hat is sealingly mounted on the housing at the second open end with the top hat having a second wall structure defining a second air gap between a second inner wall and a second outer wall. The second air gap connects with the first air gap with the second air gap being closed at its free end. A vacuum gauge is mounted on the housing for reading a vacuum contained within the air gap.

A further embodiment of the present invention is where the first basic embodiment is modified by defining that the protrusion assembly comprises a series of longitudinal ridges.

A further embodiment of the present invention is where the first basic embodiment is modified by defining that the vacuum gauge is connected directly with the second air gap.

A further embodiment of the present invention is where the first basic embodiment is modified by defining that the top hat has a second internal compartment and the vacuum gauge is located within with the second internal compartment.

A second basic embodiment of the present invention is directed to the combination of a fuel tank which has a double wall with an air gap located between the walls and a collar is mounted on the tank with the collar also having a double wall with an air gap located between the walls of the collar. A connecting passage connects between the air gap of the tank and the air gap of the collar. The air gap of the collar is defined as being open. A containment sump is to be mounted on this collar with the containment sump having a double wall defining an air gap between the walls of the containment sump with this air gap to couple with the air gap of the collar. The containment sump has an internal chamber with the ends of the internal chamber being open forming a first end and a second end. The first end is airtight sealingly attached to the collar with the air gap of the collar connecting with the air gap of the tank. The air gap of the sump includes a protrusion assembly which functions to maintain spacing of the double wall of the sump. A top hat is sealing mounted on the sump with the top hat having an air gap. The air gap of the top hat connects with the air gap of the sump. The air gap of the top hat and the air gap of the sump and the air gap of the collar forming, in essence, a single closed air gap chamber. A vacuum gauge connects with this air gap chamber.

A further embodiment of the present invention is where the second basic embodiment is modified by defining that the protrusion assembly comprises a series of longitudinal ridges.

A further embodiment of the present invention is where the second basic embodiment is modified by defining that the vacuum gauge is located within the internal chamber that is located between the top hat, the sump and the collar.

A third basic embodiment of the present invention is directed to the method of installing a containment sump on a collar of a fuel tank comprising the steps of utilizing a fuel tank which has a double wall with an air gap located between the walls of the tank where the fuel tank has a collar mounted thereon and where the collar also has an air gap and where the collar air gap couples with the tank air gap, mounting an end of a double walled containment sump on the collar where the sump has an internal open ended chamber and a double wall with an air gap and where there is located a series of protrusions within the air gap in order to maintain a space between the walls of the sump, coupling the air gap of the tank with the air gap of the sump, mounting a top hat on the free end of the sump where the top hat closes the air gap, installing a vacuum gauge in conjunction with the air gap and drawing a vacuum within the air gap to a predetermined level.

A further embodiment of the present invention is where the third basic embodiment is modified by defining that the second mounting step includes utilizing a top hat that has a double wall and an air gap between the walls of the top hat.

A further embodiment of the present invention is where the third basic embodiment is modified where the installing step comprises mounting of the vacuum gauge within the confines of the top hat.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference is to be made to the accompanying drawings. It is to be understood that the present invention is not limited to the precise arrangement shown in the drawings.

FIG. 1 is an isometric view of a typical fuel tank which is shown to include a pair of collars mounted thereon;

FIG. 2 is an enlarged isometric view of one of the collars of the fuel tank of FIG. 1;

FIG. 3 is an exploded isometric view of the different parts that make up one of the collars mounted on the fuel tank of FIG. 1;

FIG. 4 is a longitudinal cross-sectional view through one of the collars on the fuel tank of FIG. 1 showing its constructional arrangement as well as the constructional arrangement of the wall of the fuel tank;

FIG. 5 is an isometric view of the containment sump constructed in accordance with this invention on which has been mounted a top hat;

FIG. 6 is an exploded isometric view of the containment sump of the present invention and the top hat in conjunction with the collar on which it is to be mounted;

FIG. 7 is a longitudinal cross-sectional view through the top hat, containment sump and collar and fuel tank;

FIG. 8 is an exploded isometric view of the containment sump that is constructed in accordance with this invention;

FIG. 9 is an exploded isometric view of the top hat that is mounted on the containment sump; and

FIG. 10 is an enlarged view showing the double walled construction of the containment sump with the view being partially cut away to show the internal construction of the wall.

DETAILED DESCRIPTION OF THE INVENTION

Referring particularly to FIG. 1, there is shown a fuel tank 20. A typical fuel tank 20 is generally cylindrical, however fuel tank 20 could take any configuration. The fuel tank 20 is intended to be installed underground.

Mounted on the fuel tank 20 is a pair of collars 22 and 24. Collar 24 is identical to collar 22. The following detailed description relating to collar 22 is to be understood to also be applicable to collar 24. Although there are two in number of collars 22 and 24 mounted on the fuel tank 20, it is considered to be within the scope of this invention that the fuel tank 20 could have only one collar or it could have even more than two collars. Typically, a fuel tank 20 will hold thousands of gallons of gasoline, diesel fuel or oil.

The fuel tank 20 is double walled. The double wall comprises an outer wall 26 and an inner wall 28. In between the outer wall 26 and the inner wall 28 is located an air gap 30. The air gap 30 is continuous so the air gap 30 is throughout the entire area of the fuel tank 20. The purpose of the double wall and the air gap 30 is that if per chance the fuel tank 20 produces a leak that the leak will enter into the air gap 30. The leak can then be detected and contained. The air gap 30 is designed to contain a vacuum (spsi).

Mounted through the double walls 26 and 28 of the fuel tank 20 is a fill connector and a fill cap that normally closes the fill connector. The structure of the fill connector and the fill cap is shown generally in dotted lines 32. The structure of the fill connector and the fill cap is deemed to be conventional and forms no specific part of this invention.

Wherever there is a fill cap and a fill connector, there is mounted around it a collar, such as collars 22 and 24. Generally, the fuel tank 20 will be constructed of steel or fiberglass as is also the collar 22. The collar 22 will normally be in the range of about four feet in diameter. The collar 22 has an outer wall 36 which has a base that is specially configured to rest in a close conforming manner on the fuel tank 20. The outer wall 36 is to be airtight, sealingly secured to the fuel tank 20 by means of a fiberglass seal 38. Except for the area of the seal 38, the entire exterior surface of the outer wall 36 is coated with a gel coat that produces a smooth finish that prevents penetration by water, dirt, etc. and eliminates deterioration. A typical gel coat would be Hydroshield®, LHM-2900, manufactured by H.K. Research Corporation of Hickory, N.C. The structure of the fiberglass seal 38 is deemed to be conventional and forms no specific part of this invention except that it is utilized in conjunction therewith. The collar 22 also includes an inner wall 40 which is circular in configuration. The inner wall 40 has an exterior surface that is formed to include a series of longitudinal ridges 42. The non-sealed areas of the inner wall 40 are also gel coated. Between each directly adjacent pair of ridges 42 is located a groove 44. The grooves 44 connect with an annular groove 46. It is the function of the ridges 42 to maintain a spacing between inner wall 40 and outer wall 36. If it were not for the ridges 42, when a vacuum is drawn within the air gap 48 located between the outer wall 36 and the inner wall 40, the inner wall 40 and outer wall 36 would tend to be drawn together and be in flush contact therebetween. Such a flush contact is not desirable. A leak could occur within the collar 22 and such would not be picked up by the vacuum gauge 50. The vacuum gauge 50 is connected by a manually operated valve 52 to the air gap 48. The air gap 48 is also coupled to the air gap 30 by means of a connecting tube 54. The inner wall 40 is airtight sealingly mounted in position on the fuel tank 20 by means of a fiberglass seal 56 which is basically similar to the seal 38.

A fiberglass lid 58 is attached on the free upper edge of the outer wall 36 and the inner wall 40 that are located in annular juxtaposition. The lid 58 comprises a length of fiberglass mat, which is not shown, to which has been applied a resin with the result that the lid 58 is airtight sealingly mounted onto the outer wall 36 and the inner 40. Prior to shipping of the fuel tank 20 to the installing location, a vacuum (about 5 psi) is to be drawn within the air gaps 30 and 48 and then the amount of vacuum is to be ascertained by the gauge 50. If the vacuum is not held, this means that there is a leak in the construction of the fuel tank 20 and it would either have to be repaired or discarded. If the vacuum does hold, then the fuel tank 20 is ready to be shipped to the installing location.

At the installing location, the installer proceeds to cut along line 60 through the lid 58 exposing the air gap 48. The installer then mounts a containment sump 62 onto the upper edge of the collar 22. Outer wall 64 aligns with outer wall 36 and inner wall 66 aligns with inner wall 40. The unsealed surfaces of the walls 64 and 66 are also gel coated. Between the outer wall 63 and the inner wall 66 there is located an air gap 68. The width of the air gap 68 is about the same as the width of air gap 48 which is also about the same width as air gap 30. The exterior surface of the inner wall 66 has formed thereon a series of longitudinal ridges 70.

Between each directly adjacent pair of longitudinal ridges 70 there is a groove 72.

Each end of each groove 72 connects to an annular groove 74. The annular groove 74 makes sure that all the grooves 72 interconnect so that the vacuum that is applied within the air gap 68 is evenly dispersed and the ridges 70 prevent the outer wall 64 and the inner wall 66 from joining together in a flush arrangement. Again, if the outer wall 64 and the inner wall 66 did become flush, there would produced areas that would not be detected if a leak developed in those particular areas.

It is to be understood that although ridges 42 and 70 are shown, it is considered to be within the scope of this invention that other types of protrusions could be used that would tend to maintain the air gap spacing between the outer wall 64 and the inner wall 66. One other type of protrusion would be a mass of bumps that would be evenly spread across the exterior surface of the inner wall 66. It is also to be considered to be within the scope of this invention that the ridges 70 could be mounted on the inside surface of the outer wall 64.

Applied with a resin is a mat strap 76 which will cover the joint between the outer walls 36 and 64. A similar mat strap 78 is mounted to cover the joint between the inner walls 40 and 66. The mat straps 76 and 78 are then respectively covered with a fiberglass seal 80 and 82. As a result, the air gap 68 is coupled directly to air gap 48 of the collar 22. The length of the containment sump 62 will generally be in the range of five feet. It is to be remembered that the fuel tank 20 is to be buried underground and the containment sump 62 is to provide for access from the ground level to within the internal chamber 84 of the containment sump 62 and the internal chamber 86 of the collar 22. The gauge 50, valve 52 and connecting tube 54 are all located within the confines of the internal chamber 86. There will also be included within the combined internal chambers 84 and 86 appropriate piping which will connect with the fuel connector, which is shown generally by dotted lines 32.

The outer wall 64 is enlarged at its upper free end forming an expanded joint 88. Within the expanded joint 88 is to be located the outer wall 90 and inner wall 92 of a top hat 94. Located between the outer wall 90 and the inner wall 92 is an air gap 96 which connects with the air gap 68. The top hat 94 has an octagonal shaped base 98. This octagonal shape base 98 is similarly utilized in both the outer wall 90 and the inner wall 92. The main portion of the containment sump 62 has this similar octagonal configuration. When the outer wall 90 and the inner wall 92 are mounted within the expanded joint 88, the installer is to apply an outside fiberglass seal 100 and an inside fiberglass seal 102. The result is an airtight connection is now established between the top hat 94 and the containment sump 62. It is to be understood that in order to insure that the air gap 96 is maintained that there is included on the exterior surface of the inner wall 92 a series of longitudinal ridges 104 with a groove 106 being located between each directly adjacent pair of ridges 104. The grooves 106 connect with an annular groove 108. A U-shaped ring 110 is placed on the free edge of the outer wall 90 and the inner wall 96 covering same. An airtight fiberglass seal 112 is then applied to the ring 110 airtight sealing same to the outer wall 90 and the inner wall 92. Included within the confines of the internal chamber 114 of the top hat 94 is a vacuum gauge 116. The vacuum gauge 116 connects with the air gap 96 and hence connects with the air gap 66, 48 and 30.

The reason there is included a separate vacuum gauge 116 is that the vacuum gauge 116 is located near the open mouth of the top hat 94. It would be difficult for a user to observe the vacuum gauge 50 because that is four or five feet from the open end of the top hat 94. It is to be understood that normally there will be placed a closing lid, not shown, across the open mouth of the top hat 94 when access into the internal chambers 114, 84 and 86 is not required.

The discussion included in this patent is intended to serve as a basic description. The reader should be aware that the specific discussion may not explicitly describe all embodiments possible and alternatives are implicit. Also, this discussion may not fully explain the generic nature of the invention and may not explicitly show how each feature or element can actually be representative of a broader function or of a great variety of alternative or equivalent elements. Again, these are implicitly included in this disclosure. Where the invention is described in device-oriented terminology, each element of the device implicitly performs a function. Apparatus claims may not only be added for the device described, but also a method claim is added to address the method of making the invention. It should also be understood that a variety of changes may be made without departing from the essence of the invention. Such changes are also implicitly included in the description. These changes still fall within the scope of this invention.

Further, each of the various elements of the invention and claims may also be achieved in a variety of manners. This disclosure should be understood to encompass each such variation, be it a variation of any apparatus embodiment, a method embodiment, or even merely a variation of any element of these. Particularly, it should be understood that as the disclosure relates to elements of the invention, the words for each element may be expressed by equivalent apparatus terms or method terms—even if only the function or result is the same. Such equivalent, broader, or even more generic terms should be considered to be encompassed in the description of each element or action. Such terms can be substituted where desired to make explicit the implicitly broad coverage to which this invention is entitled. It should be understood that all actions may be expressed as a means for taking that action or as an element which causes that action. Similarly, each physical element disclosed should be understood to encompass a disclosure of the action which that physical element facilitates. Such changes and alternative terms are to be understood to be explicitly included in the description. 

1. A method of installing a containment sump on a collar of a fuel tank comprising the steps of: utilizing a fuel tank which has a double wall with an air gap located between the walls of the tank and where the fuel tank has a collar mounted thereon where the collar also has an air gap and wherein the collar air gap couples with the tank air gap; mounting an end of a double walled containment sump on said collar where said sump has an internal open ended chamber and a double wall with an air gap and where there is located a series of protrusions within said air gap in order to maintain a space between said walls of said sump and preventing the walls from assuming a flush abutting contact; coupling said air gap of said tank with said air gap of said sump; mounting a top hat on a free end of said sump where said top hat closes said air gap; and installing a vacuum gauge in conjunction with said air gap; and drawing a vacuum within said air gap to a predetermined level.
 2. The method as defined in claim 1 wherein the second mounting step includes: utilizing a top hat that has a double wall and an air gap.
 3. The method as defined in claim 1 wherein the installing step comprising: mounting said vacuum gauge within the confines of an internal chamber of said top hat. 